I just bought more Sonos speakers to add to my system. 11 speakers and devices in all that continue to serve me without issues.

Sonos sure seems to be selling well on ebay and other used outlets.

List yours cheap and I may even bid on a few if I can fit them in here.

Good luck in finding something similar that you are going to be happy with long term.

Sorry, but I totally understand, what You are struggeling with. 

I also am very sorry for the proposed solution. Which is none. Selling the Sonos products online makes sense, after finding an alternative. 

If I found a suitable other solution, I would offer my Sonos products for sale immediately. 

If you find a solution,please keep me updated.